Chemical Vapor Deposition (CVD) and Atomic Layer Deposition (ALD) have been applied as main deposition techniques for producing thin films for semiconductor devices. These methods enable the achievement of conformal films (metal, oxide, nitride, silicide, etc.) through fine tuning of parameters during the deposition processes. Mainly the film growth is controlled by chemical reactions of metal-containing compounds (precursors) and the development of optimum precursors is essential under prediction of their properties and reaction processes.
Films of transition metals and transition metal silicide, particularly manganese, iron, cobalt, and ruthenium, are becoming important for a variety of electronics and electrochemical applications. For example, cobalt thin films are of interest due to their high magnetic permittivity. There are many reports of using cobalt thin films to form cobalt disilicide (CoSi2) for Ohmic contacts owing to its low resistivity in front-end-of-the-line processing of semiconductor devices. Cobalt containing thin films were recently studied as Cu/low-k barriers, passivation layers, and capping layers for ultra-large scale integrated devices.
Synthesis of silylamide compounds has been reported (Monatsh. Chem. (1963), 94(6), pp. 1007-1012; Polyhedron 22 (2003) pp. 67-73, J.C.S. Chem. Comm. (1972) pp. 872-873; Inorg. Chem. (1984) 23, 4584-4588; U.S. Pat. No. 6,969,539B2). Vapor deposition film formation using silylamide compounds has also been reported. (Chem. Vap. Deposition 1995, 1, No. 2, 49-51; R. G. Gordon et al; US 2009/0053426A1 Applied Materials; US 2014/0255606 Applied Materials).
Selecting a Co-containing precursor that is suitably volatile while remaining stable enough for use in vapor phase film deposition is important for commercial implementation and not always easily determined.